Ultrasound contrast plane wave imaging with higher CTR based on pulse inversion bubble wavelet transform

Although ultrasound contrast plane wave imaging can avoid the repeated disruption and capture the transient spatial distribution of microbubbles, it is still limited by lower contrast-to-tissue ratio (CTR) due to low negative peak pressure and lacks of transmit focus. The purpose of this paper was to develop an ultrasound contrast plane wave imaging method combined with pulse inversion bubble wavelet transform imaging (PIWI) technique to improve the CTR of plane wave images. First, a pair of 'bubble wavelets' was constructed by microbubbles scattering echoes predicted by modified Herring equation driven by two inverted plane waves. Next, the original echoes from such plane waves were performed by bubble wavelet correlation analysis. Then, such echoes replaced by the maximal wavelet correlation coefficients were summed to distinguish echoes of microbubbles and tissues. In vivo rabbit kidney experiments, the CTR of plane wave imaging was improved to 15.19 dB by PIWI technique without the sacrifice of image frame, which was larger 4.48±0.96 dB than that of raw images. In summary, this method could contribute to plane wave imaging by allowing the continuous transient monitoring of the accumulation of microbubbles with higher CTR.